The present invention relates to a rolling device having a rolling element and, particularly, to a rolling bearing, a linear system, and a ball screw. Further, the invention relates to a method of manufacturing a rolling device and, particularly, to a method of manufacturing a rolling bearing, a leaner system, or a ball screw.
As a rolling bearing, a ball bearing described in JP-A-8-312652 has heretofore been known.
The rolling bearing is provided with an outer ring, an inner ring, a plurality of balls, and a solid lubricating composition, in which the solid lubricating composition is disposed between the outer ring and the inner ring.
The solid lubricating composition is made from a mixture of resin material and lubricant. The solid lubricating composition is filled between the outer ring and the inner ring in a fluid state to be heated to a temperature of 150° C. or more that is higher than a melting point of the resin material, followed by solidification by cooling.
Since the solid lubricating composition is used as the lubricant in the conventional ball bearing, it is possible to reliably lubricate the bearing ring and the balls under severe lubrication conditions such as a high load, a high temperature, and a impact load, while a hardness of the inner and outer rings and the rolling element is sometimes reduced due to the temperature of 150° C. or more because of the necessity of heating a temperature around the inner and the outer rings to the temperature of 150° C. or more for melting the solid lubricating composition.
The inner and outer rings and the rolling element are formed from a steel material such as high carbon chrome bearing steel, case hardened steel, and high speed tool steel each of which is hardened by a heat treatment such as quenching, carburizing, carbonitriding, carburizing quenching, and tempering. However, the hardness is reduced due to a temperature equal to or higher than the tempering temperature, for example, resulting in a reduced hardness. Therefore, in the case of heating to the temperature of 150° C. or more, it is necessary to perform a heat treatment in which a tempering temperature is higher than a heating temperature or perform rapid cooling, thereby undesirably increasing a cost or requiring more strict temperature and time control.
Also, since a long time is required for increasing the temperature around the inner and outer rings to the temperature of 150° C. or more at which the resin is melted, a cycle time in manufacture of ball bearings is increased.